Even so, a lot of this is what we call 'internet culture' and basically there are two major layers to the internet. The upper layer is 'normie' internet: Facebook, Twitter, YouTube, BuzzFeed, E-Mail, etc... Things the majority of people who are not really into internet culture use it for.
Then there's the sub layer, which is the internet that most of us know: Web forums, fan sites, image boards, etc...
To give you an example of how completely out of touch with the internet subculture most people actually are, if you asked a general selection of people who PewDiePie is for example, someone who is pretty well known on the internet, even if you don't actually watch him, I'd put money on the fact that a good 80% of that group would not know who he is. We take for granted that most people would know who Pepe is, or who Markiplier is or what Furries or Penny Arcade is because they are things that we generally are exposed to often enough for them to be 'common knowledge' even if they are things we don't specifically have an interest in or spend time to know about.
However outside of this internet culture such terms are completely alien and most people have no idea what any idea what any of those things are, and for people like us who consider them things as common as Star Wars that you assume everyone should know about, when we run across people who have never heard of them it can seem alien to us. Like running into someone who has never heard of Star Wars.
They are actually the majority, however.